A union boss has warned rail strikes will continue until a settlement is reached as the latest walkout by workers caused widespread disruption for train passengers.
Speaking to Sky News, RMT chief Mick Lynch said his members were "completely committed to the cause" and would "keep going" in their long-running dispute over pay, jobs and conditions.
But cabinet minister James Cleverly has condemned the latest walkouts arguing that working people were being "held hostage" by the unions.
It came as fresh strike action by a number of unions hit the rail network, with only around a fifth of services running, and half of lines closed, with a further walkout planned for Saturday.
London Underground and buses in the capital will also be hit by industrial action on Friday.
The knock-on effect of the rail stoppages will impact services into Sunday.
People who are not able to travel on Thursday or Saturday are able to use their ticket either the day before or up until the 23 August, or claim a refund.
Mr Lynch said: "Nobody can afford to go on strike. They don't want to be on strike, they want a settlement.
"They are completely tied into this dispute.
"I addressed a meeting of thousands of our members last night online and they are totally committed to the campaign that we have got.
"They understood the issues when they voted for it and they are showing on the picket lines that they are completely committed to the cause.
"We will keep going until we get a negotiated settlement and our members will decide whether it's acceptable or not."
Predicting that strikes would extend to other areas amid employee discontent, Mr Lynch said: "There's a wave of reaction amongst working people to the way they are being treated. People are getting poorer every day of the week. People can't pay their bills.
"They are getting treated despicably in the workplace. I think there will be generalised and synchronised action - it may not be in the traditional form.
"I think there is a massive response coming from working people because they are fed up with the way they are being treated."
But hitting out at the industrial action, Mr Cleverly said: "The rail unions are there to look after their members and... they have done that very effectively.
"They have got a very, very good salary package. They have incredibly good, ridiculously good terms and conditions.
"And what they are doing through these strikes is they are disadvantaging people trying to get to work, trying to put food on the table, trying to keep a roof over their heads.
"These strikes are unfair and completely inappropriate and it's wrong that people are held hostage by the unions in this way."